"Up until" is a commonly used phrase that indicates a certain point of time or occurrence. However, there are several synonyms that convey the same meaning and can be used to avoid repetition or add variety to our writing. Some examples include "prior to," "before," "until," "till," "by," and "leading up to." These phrases can be used interchangeably depending on the context and tone of the piece. While they may seem small and insignificant, using such synonyms can improve the overall flow and style of our writing.